The invention relates generally to vehicle safety devices and more particularly to a device for protecting users from unsafe levels of carbon monoxide caused by vehicle operation in an enclosed space.
The dangers of carbon monoxide (CO) poisoning are well known. At high levels, carbon monoxide is toxic to humans. Many modern processes have the potential to produce lethal amounts of CO, and one of the most common places where carbon monoxide poisoning occurs is in the home, whether from a furnace or space heater malfunction, or from an unattended vehicle running in a closed garage.
CO is a gas that is odorless and colorless, therefore, it is difficult if not impossible for humans to detect that they are being poisoned, particularly while sleeping. For this reason, devices have been developed to monitor air quality and sound an alarm if a toxic level of CO is detected, similar to a smoke detector.
There are several types of sensors used in CO detectors. The simplest is a pad containing a chemical that changes color when exposed to CO. A biomimetic sensor operates similarly but uses chemicals that darken in proportion to the amount of CO in the environment, thus providing a more fine-tuned and reliable detection. An electrochemical sensor uses a fuel cell that generates a signal current related to the amount of CO in the atmosphere. Finally, a semiconductor sensor includes a sensing element that responds to CO in the atmosphere by changing its resistance, which can be monitored by an integrated circuit.
All of these sensors have downsides. The first three are chemical based, and therefore have a useful operational lifespan of approximately 5-7 years, sometimes much less. The semiconductor sensor must be heated to approximately 400° C., resulting in a large power demand and a useful lifespan of approximately 5-10 years. In addition, CO detectors are sensitive to their environment, and become less effective in environments experiencing temperature extremes, such as would exist in a garage, for example.
Thus, a need exists for a simple-to-use, reliable device that will protect against CO poisoning in a wide range of operating environments by detecting the root cause of the CO generation.